Liquid chromatography coupled with time‐of‐flight tandem mass spectrometry for comprehensive phenolic characterization of pomegranate fruit and flower extracts used as ingredients in botanical dietary supplements

Pomegranate (Punica granatum L.) fruit and flower extracts, which are rich sources of bioactive phenolics, are widely utilized as ingredients in botanical dietary supplements. While the phenolic characterization of extracts of pomegranate fruit has been previously studied by liquid chromatography with tandem mass spectrometry, there is lack of similar data for pomegranate flowers. Herein, liquid chromatography with time‐of‐flight tandem mass spectrometry was utilized to comprehensively characterize the phenolics present in two pomegranate extracts, previously studied for their in vitro and in vivo biological effects, namely, a patented commercial pomegranate fruit extract (Pomella®), and a pomegranate flower extract. Seventy‐one phenolics were characterized in the pomegranate fruit extract with the vast majority identified in the flower extract. However, only the pomegranate fruit extract contained tannin‐glucuronides and two punicalagin isomers (a characteristic pomegranate phenolic) were identified in this extract while four were identified in the flower extract. The previously reported compounds, pomellatannin and punicatannins A/B, were identified as unique chemical markers in the pomegranate fruit and flower extracts, respectively. This study will aid in the quality control, authentication, and standardization of these botanical ingredients to evaluate their potential health benefits in future planned pre‐clinical and clinical studies. Also, this is the first phenolic characterization of a pomegranate flower extract using liquid chromatography with tandem mass spectrometry.     

Ultra high performance liquid chromatography coupled with electrospray ionization/quadrupole time‐of‐flight mass spectrometry for the rapid analysis of constituents in the traditional Chinese medicine formula Wu Ji Bai Feng Pill

An ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time‐of‐flight mass spectrometry method in both positive and negative ion modes was established in order to comprehensively investigate the major constituents in Wu Ji Bai Feng Pill. Briefly, a Waters ACQUITY UPLC HSS C₁₈ column was used to separate the aqueous extract of Wu Ji Bai Feng Pill. A total of 0.1% formic acid in acetonitrile and 0.1% aqueous formic acid v/v were used as the mobile phase. All analytes were determined using quadrupole time‐of‐flight mass spectrometry with electrospray ionization source in positive and negative ion modes. At length, a total of 173 components including flavones and their glycosides, monoterpene glycosides, triterpene saponins, phenethylalchohol glycosides, iridoid glycosides, phthalides, tanshinones, phenolic acids, sesquiterpenoids and cyclopeptides were identified or tentatively characterized in Wu Ji Bai Feng Pill in an analysis of 16.0 min based on the accurate mass and tandem mass spectrometry behaviors. The developed method is rapid and highly sensitive to characterize the chemical constituents of Wu Ji Bai Feng Pill, which could not only be used for chemical standardization and quality control of Wu Ji Bai Feng Pill, but also be helpful for further study in vivo metabolism of Wu Ji Bai Feng Pill.     

Analysis of phenolic and triterpenoid compounds in licorice and rat plasma by high‐performance liquid chromatography diode‐array detection,time‐of‐flight mass spectrometry and quadrupole ion trap mass spectrometry

High‐performance liquid chromatography with diode‐array detection (HPLC/DAD), time‐of‐flight mass spectrometry (HPLC/TOFMS) and quadrupole ion trap mass spectrometry (HPLC/QITMS) were used for separation and identification of several compounds in licorice and rat plasma after oral administration of the herbal extract. Three phenolic compounds and one triterpenoid in licorice extract were unambiguously identified by comparing with the standard compounds. A formula database of known compounds in licorice was established, against which the other 42 compounds were identified effectively based on the accurate extract masses and formulae acquired by HPLC/TOFMS. In order to differentiate the isomers, tandem mass spectrometry was also used. The deduced fragmentation behaviors in QITMS were used to distinguish seven groups of isomers in licorice. By means of the three detectors, 46 compounds in licorice were identified. After oral administration of the extract, 25 compounds in rat plasma were detected and identified by comparing and contrasting the compounds measured in licorice with those in the plasma samples by HPLC/TOFMS. It is concluded that a rapid and effective method based on three analytical techniques was established, which is useful for identification of multiple compounds in licorice in vitro and in vivo. The result should be very useful for the quality control and curative mechanism study of licorice. Copyright © 2009 John Wiley & Sons, Ltd.     

Comparison of the origin and phenolic contents of Lycium ruthenicum Murr. by high‐performance liquid chromatography fingerprinting combined with quadrupole time‐of‐flight mass spectrometry and chemometrics

The fruits of Lycium ruthenicum Murr. have long been used in folk medicine. Nevertheless, detailed information related to its phenolic composition and its quality control remains scarce. In this study, a simple and reproducible method, based on high‐performance liquid chromatography combined with chemometrics, was developed to authenticate 18 samples of L. ruthenicum Murr. collected from different parts of China through fingerprint analysis. The main peaks were identified by quadrupole time‐of‐flight electrospray ionization mass spectrometry. Four phenolics were quantified, and the most abundant phenolic compound in almost all samples was kukoamine A. Hierarchical cluster analysis and principal component analysis were applied to classify these samples. Also, a total of 26 compounds, which were mainly phenolic compounds and anthocyanins, were identified or tentatively identified based on the available literature and standard references. Among these, 16 were reported for the first time in the extract. The results showed that there was no significant difference between L. ruthenicum fruits from different provinces in terms of chemical composition. Also, the fingerprint together with chemometric analyses and quadrupole time‐of‐flight electrospray ionization mass spectrometry are promising methods for evaluating the quality consistency, identification, and comprehensive evaluation of L. ruthenicum .     

High‐speed counter‐current chromatography assisted preparative isolation of bioactive compounds from stem bark of Juglans mandshurica

High‐speed counter‐current chromatography was applied for the first time for the separation and purification of bioactive compounds contained in the stem bark of Juglans mandshurica Maxim. Silica gel column chromatography was first used to obtain three composition‐enriched target fractions from a crude J. mandshurica methanol extract. Three independent high‐speed counter‐current chromatography processes were then used to further isolate 13 bioactive compounds, namely, six galloyl glucose derivatives, three flavonones, three naphthoquinones, and ethyl gallate. The isolates were identified by ultrahigh‐performance liquid chromatography with tandem mass spectrometry, and ultraviolet and NMR spectroscopy, and compared with literature data. Their purities were determined to be >94.6% by ultrahigh performance liquid chromatography. Furthermore, based on the total phenolic content and results of a 2,2‐diphenyl‐1‐picrylhydrazyl test, the methanol extract and two of the three initial fractions were observed to be rich in phenolic compounds and exhibit good free radical scavenging abilities, while nine of the isolated compounds exhibited remarkable antioxidant activity, superior to that of butyrate hydroxy‐toluene and comparable to that of gallic acid. The results of this research confirm the effectiveness of high‐speed counter‐current chromatography for the separation of compounds contained in extremely complex samples, and provide a basis for the further utilization of J. mandshurica .     

Identification of metabolites in WZS‐miniature pig urine after oral administration of Danshen decoction by HPLC coupled with diode array detection with electrospray ionization tandem ion trap and time‐of‐flight mass spectrometry

Danshen (DS) is a widely used traditional Chinese medicine for treating cardiovascular and cerebrovascular diseases. A simple, rapid and sensitive method was developed for identification of the in vivo metabolites in urine of WZS‐miniature pigs after oral administration of DS decoction by HPLC coupled with diode array detection with electrospray ionization tandem ion trap and time‐of‐flight mass spectrometry. This method has been successfully applied to simultaneous identification of 50 compounds (including 11 new ones) in pig urine. In addition, one new compound, (3‐hydroxyphenyl) crylic acid glycine methyl ester (C1), along with eight known ones were first isolated by column chromatography and identified by spectroscopic means, including 1D/2DNMR and mass spectrometry, as reference substances. Ten phenolic compounds (protocatechuic aldehyde, protocatechuic acid, caffeic acid, danshensu, ferulic acid, isoferulic acid, rosmarinic acid and salvianolic acid A/B/D) were found to be the main absorbed original constituents of DS decoction, which underwent the metabolic reactions of glucuronidation, sulfation, methylation, hydrogenation and glycine conjugation in vivo. In conclusion, the developed method is applicable to the analysis and identification of constituents in biological matrices after administration of DS decoction. Copyright © 2012 John Wiley & Sons, Ltd.     

Phenolic composition of pomegranate peel extracts using an liquid chromatography‐mass spectrometry approach with silica hydride columns

The peels of different pomegranate cultivars (Molla Nepes, Parfianka, Purple Heart, Wonderful and Vkunsyi) were compared in terms of phenolic composition and total phenolics. Analyses were performed on two silica hydride based stationary phases: phenyl and undecanoic acid columns. Quantitation was accomplished by developing a liquid chromatography with mass spectrometry approach for separating different phenolic analytes, initially in the form of reference standards and then with pomegranate extracts. The high‐performance liquid chromatography columns used in the separations had the ability to retain a wide polarity range of phenolic analytes, as well as offering beneficial secondary selectivity mechanisms for resolving the isobaric compounds, catechin and epicatechin. The Vkunsyi peel extract had the highest concentration of phenolics (as determined by liquid chromatography with mass spectrometry) and was the only cultivar to contain the important compound punicalagin. The liquid chromatography with mass spectrometry data were compared to the standard total phenolics content as determined by using the Folin–Ciocalteu assay.     

Isolation,purification, and identification of the main phenolic compounds from leaves of celery (Apium graveolens L. var. dulce Mill./Pers.)

We developed a simple and meaningful preparative method for the separation and purification of the main phenolic compounds from the leaves of celery (Apium graveolens L. var. dulce Mill./Pers.) and we established an accurate and specific analytical method for the identification of the main phenolic compounds from celery leaves. The crude extract from celery leaves was prefractioned by polyamide resin to enrich the phenolic compounds. They were then purified further by preparative high‐performance liquid chromatography, and seven main phenolic compounds were obtained: including chlorogenic acid, luteolin 7‐O‐β‐d‐ apiofuranosyl(1→2)‐β‐d‐ glucopyranoside, luteolin 7‐O‐β‐d‐ glucopyranoside, apiin, chrysoeriol 7‐O‐β‐d‐ apiofuranosyl(1→2)‐β‐d‐ glucopyranoside, luteolin 7‐O‐[β‐d‐ apiofuranosyl(1→2)‐(6′′‐O‐malonyl)]‐β‐d‐ glucopyranoside, and apigenin 7‐O‐[β‐d‐ apiofuranosyl(1→2)‐(6′′‐O‐malonyl)]‐β‐d‐ glucopyranoside. Their purities were measured by using high‐performance liquid chromatography, and their chemical structures were confirmed using UV spectrophotometry, ultra high performance liquid chromatography with quadrupole time‐of‐flight tandem mass spectrometry, and NMR spectroscopy. Our studies indicate that preparative high‐performance liquid chromatography combined with polyamide resin is a simple and meaningful preparative method for the separation and purification of phenolic compounds from the leaves of celery or other plants, and the use of UV spectrophotometry, ultra high performance liquid chromatography with quadrupole time‐of‐flight tandem mass spectrometry, and NMR spectroscopy is an accurate and specific analytical method for the identification of phenolic compounds.     

Comparison of the chemical profiles of fresh‐raw and dry‐processed Juglans mandshurica

The processing of Juglans mandshurica Maxim. is important to reduce its toxicity and enhance its efficacy. Simple, efficient, and sensitive ultra‐high performance liquid chromatography coupled with a time‐of‐flight mass spectrometry based chemical profiling approach was proposed to rapidly evaluate the chemical difference between fresh and dry samples. Under the optimized ultra‐high performance liquid chromatography and quadrupole time‐of‐flight tandem mass spectrometry conditions, 81 significantly different compounds were rapidly discovered using principal component analysis, and then tentatively identified by comparison with reference substances or inferred through mass spectral fragment ion analysis and literature data. These compounds included 35 naphthoquinones, 11 diarylheptanoids, nine flavonoids, eight triterpenes, 12 phenolic acids, and six aliphatics. The results demonstrated that chemical reactions occurring during processing could be used to elucidate the processing mechanism of Juglans mandshurica Maxim. This study provides a novel approach to identifying complicated components of various complex mixtures in fresh‐raw and dry‐processed traditional Chinese medicines, which could be used as a valid analytical method to further understand the processing mechanisms of these medicines, as well as providing intrinsic quality control of the medicines and their processed products.     

Multiconstituent identification in root,branch, and leaf extracts of Juglans mandshurica using ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry

As a traditional medicinal plant, Juglans mandshurica has been used for the treatment of cancer. Different organs of this plant showed anti‐tumor activity in clinic and laboratory. Comparative identification of constituents in different plant organs is essential for investigation of the relationship between chemical constituents and pharmacological activities. For this aim, the roots, branches, and leaves of J. mandshurica were extracted with 50% v/v methanol and then subjected to ultra‐high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry analysis conducted under low and high energy. As a result, we have to date identified 111 compounds consisting of 56 tannins, 29 flavonoids, 13 organic acids, 8 naphthalene derivatives, and 5 anthracenes. Five compounds, namely, diquercetin trihydroxy‐truxinoyl‐glucoside, two quercetin kaempferol dihydroxy‐truxinoyl‐glucosides, syringoyl‐tri‐galloyl‐O‐glucose, and dihydroxy‐naphthalene syringoyl‐glucoside, were tentatively identified as new compounds. Of the compounds identified, 76 were found in the root extract, 67 in the branch extract, and 37 in the leaf extract. Only six compounds including four organic acids and two tannins were found in all three extracts. We developed a rapid and sensitive ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry approach to identify multiple constituents of complex extracts without separation and ion selection. The results presented provide useful information on further research of the bioactive compounds of J. mandshurica .     

Identification of chemical constituents and rat metabolites of Kangxianling granule by HPLC‐Q‐TOF‐MS/MS

A high‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass tandem mass spectrometry method was established to characterize the chemical constituents of Kangxianling granule (KXL), a traditional Chinese medicine formula, and the metabolic profile in rat urine and plasma after oral administration of KXL. A total of 27 compounds in KXL extract and 13 prototype compounds with 12 metabolites in rat urine and plasma were identified. Among the 27 detected compounds, 15 were identified by comparing the retention time and MS data with that of reference compounds and the other 12 compounds were tentatively assigned based on the MS data and reference literature. The main prototype components absorbed in rat were amygdalin, salvianolic acid B, tanshinones and anthraquinones. Hydroxylation, glucuronidation and sulfation were the principal metabolic pathways in rat. The results revealed that the 25 compounds identified in rat urine and plasma were the potential active ingredients of KXL, which provides helpful chemical information for further study of the pharmacology mechanism of KXL. Copyright © 2015 John Wiley & Sons, Ltd.     

Systematic characterization and simultaneous quantification of the multiple components of Rhododendron dauricum based on high‐performance liquid chromatography with quadrupole time‐of‐flight tandem mass spectrometry

Rhododendron dauricum L. has been used as a traditional Chinese medicine to treat cough and asthma and relieve phlegm and bronchitis. In this study, a reliable method based on high‐performance liquid chromatography with diode array detection and quadrupole time‐of‐flight tandem mass spectrometry was established to systematically identify and quantify the components in this herb for the first time. A total of 33 compounds were identified, including 24 flavonoids, six phenolic acids, two coumarins and one terpene. Among them, poriolin ( 17 ), farrerol‐7‐O‐β‐d‐ glucopyranoside ( 20 ), and syzalterin ( 30 ) were isolated from this plant for the first time, and quercetin‐3‐β‐d‐ (6‐p‐hydroxy benzoyl) galactoside ( 19 ), quercetin‐3‐β‐d‐ (6‐p‐coumaroyl) galactoside ( 21 ), and myrciacetin ( 23 ) were identified from this genus for the first time. Fragmentation pathways of flavonoids also have been investigated by electrospray ionization mass spectrometry. Moreover, seven bioactive constituents, namely, gallic acid ( 1 ) , scopoletin (6 ), dihydroquercetin ( 7 ), quercetin ( 22 ), kaempferol ( 25 ), 8‐desmethyl farrerol ( 27 ), and farrerol ( 28 ), were simultaneously quantified. The developed method has been validated and applied to analyze ten samples of R. dauricum from Hebei Province successfully. The contents of the seven compounds have been detected and compared.     

Comprehensive identification of potential antioxidant components in the aerial parts of Polygonum chinense L. var. hispidum using ultra high performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry

The aerial parts of Polygonum chinense L. var. hispidum are one of the key herbs in Cantonese herbal tea, which is quite a common local beverage in LingNan area of China. Previous investigation has found that this herb possesses antioxidant activity and the ethyl acetate fraction of its ethanol extract shows the strongest antioxidant activity. However, little is known about its antioxidant chemical constituents. The aim of this research was to investigate the active constituents of this plant by identifying and characterizing the chemical profile in ethyl acetate fraction using ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry, which can provide characteristic ultraviolet absorption, accurate molecular weight, and diagnostic tandem mass spectrometry fragment ions. As a result, 85 compounds were identified including 22 flavonoids, 12 ellagic acids, 34 ellagitannins, 16 phenolic acids, and one phenolic amide. All the phenolic compounds identified in this work, especially ethyl gallate, geraniin, chebulagic acid, and quercitrin with the higher peak areas in the ultra high performance liquid chromatography with mass spectrometry chemical profile of this plant, could be the bioactive principles responsible for the antioxidant activity. These findings in the present study could benefit further studies involving the functions and chemicals of this plant, and provide scientific evidence for usage of Cantonese herbal tea.     

High‐speed separation and characterization of major constituents in Radix Paeoniae Rubra by fast high‐performance liquid chromatography coupled with diode‐array detection and time‐of‐flight mass spectrometry

A fast high‐performance liquid chromatography (HPLC) method coupled with diode‐array detection (DAD) and electrospray ionization time‐of‐flight mass spectrometry (ESI‐TOFMS) has been developed for rapid separation and sensitive identification of major constituents in Radix Paeoniae Rubra (RPR). The total analysis time on a short column packed with 1.8‐µm porous particles was about 20 min without a loss in resolution, six times faster than the performance of a conventional column analysis (115 min). The MS fragmentation behavior and structural characterization of major compounds in RPR were investigated here for the first time. The targets were rapidly screened from RPR matrix using a narrow mass window of 0.01 Da to restructure extracted ion chromatograms. Accurate mass measurements (less than 5 ppm error) for both the deprotonated molecule and characteristic fragment ions represent reliable identification criteria for these compounds in complex matrices with similar if not even better performance compared with tandem mass spectrometry. A total of 26 components were screened and identified in RPR including 11 monoterpene glycosides, 11 galloyl glucoses and 4 other phenolic compounds. From the point of time savings, resolving power, accurate mass measurement capability and full spectral sensitivity, the established fast HPLC/DAD/TOFMS method turns out to be a highly useful technique to identify constituents in complex herbal medicines. Copyright © 2008 John Wiley & Sons, Ltd.     

Characterization of phenolic compounds in green and red oak‐leaf lettuce cultivars by UHPLC‐DAD‐ESI‐QToF/MS using MSE scan mode

Lettuce (Lactuca sativa ) is one of the most popular leafy vegetables in the world and constitutes a major dietary source of phenolic compounds with health‐promoting properties. In particular, the demand for green and red oak‐leaf lettuces has considerably increased in the last years but few data on their polyphenol composition are available. Moreover, the usage of analytical edge technology can provide new structural information and allow the identification of unknown polyphenols. In the present study, the phenolic profiles of green and red oak‐leaf lettuce cultivars were exhaustively characterized by ultrahigh‐performance liquid chromatography (UHPLC) coupled online to diode array detection (DAD), electrospray ionization (ESI), and quadrupole time‐of‐flight mass spectrometry (QToF/MS), using the MS^E instrument acquisition mode for recording simultaneously exact masses of precursor and fragment ions. One hundred fifteen phenolic compounds were identified in the acidified hydromethanolic extract of freeze‐dried lettuce leaves. Forty‐eight of these compounds were tentatively identified for the first time in lettuce, and only 20 of them have been previously reported in oak‐leaf lettuce cultivars in literature. Both oak‐leaf lettuce cultivars presented similar phenolic composition, except for apigenin‐glucuronide and dihydroxybenzoic acid, only detected in the green cultivar; and for luteolin‐hydroxymalonylhexoside, an apigenin conjugate with molecular formula C₄₀H₅₄O₁₉ (monoisotopic MW = 838.3259 u ), cyanidin‐3‐O ‐glucoside, cyanidin‐3‐O ‐(3″‐O ‐malonyl)glucoside, cyanidin‐3‐O ‐(6″‐O ‐malonyl)glucoside, and cyanidin‐3‐O ‐(6″‐O ‐acetyl)glucoside, only found in the red cultivar. The UHPLC‐DAD‐ESI‐QToF/MS^E approach demonstrated to be a useful tool for the characterization of phenolic compounds in complex plant matrices.     

Qualitative and quantitative analysis of major constituents from Dazhu Hongjingtian capsule by UPLC/Q‐TOF‐MS/MS combined with UPLC/QQQ‐MS/MS

In this work, a sensitive and efficient method was established and validated for qualitative and quantitative analysis of major bioactive constituents in Dazhu Hongjingtian capsule by liquid chromatography tandem mass spectrometry. A total of 32 compounds were tentatively identified using ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry. Furthermore, 12 constituents, namely gallic acid, 3,4‐dihydroxybenzoic acid, salidroside, p‐ coumaric acid‐4‐O ‐β ‐d ‐glucopyranoside, bergeninum, 4‐hydroxybenzoic acid, 4‐hydroxyphenylacetic acid, syringate, 6′′‐O ‐galloylsalidroside, rhodiosin, rhodionin and kaempferol‐7‐O ‐α ‐l ‐rhamnoside, were simultaneously quantified by the developed ultra‐performance liquid chromatography coupled with a triple quadrupole mass spectrometry method in 9 min. All of them were analyzed on an Agilent ZorBax SB‐C₁₈ column (3.0 × 100 mm, 1.8 μm) with linear gradient elution of methanol–0.1% formic acid water. The proposed method was applied to analyze three batches of samples with acceptable linearity (R , 0.9979–0.9997), precision (RSD, 1.3–4.7%), repeatability (RSD, 1.7–4.9%), stability (RSD, 2.2–4.9%) and recovery (RSD, 0.6–4.4%) of the 12 compounds. As a result, the analytical method possessing high throughput and sensitivity is suitable for the quality control of Dazhu Hongjingtian capsule.     

Simultaneous quantification of 25 active constituents in the total flavonoids extract from Herba Desmodii Styracifolii by high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry

A sensitive and selective high‐performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry method has been developed and validated for the simultaneous determination of 25 active constituents, including 21 flavonoids and four phenolic acids in the total flavonoids extract from Herba Desmodii Styracifolii for the first time. Among the 25 compounds, seven compounds including caffeic acid, acacetin, genistein, genistin, diosmetin, diosmin and hesperidin were identified and quantified for the first time in Herba Desmodii Styracifolii. Chromatographic separation was accomplished on a ZORBAX SB‐C₁₈ (250 mm×4.6 mm, 5.0 μm) column using gradient elution of methanol and 0.1‰ acetic acid v/v at a flow rate of 1.0 mL/min. The identification and quantification of the analytes were achieved using negative electrospray ionization mass spectrometry in multiple‐reaction monitoring mode. The method was fully validated in terms of limits of detection and quantification, linearity, precision and accuracy. The results indicated that the developed method is simple, rapid, specific and reliable. Furthermore, the developed method was successfully applied to quantify the 25 active components in six batches of total flavonoids extract from Herba Desmodii Styracifolii.     

Sequential ultrasonic extraction of a Chinese coal and characterization of nitrogen‐containing compounds in the extracts using high‐performance liquid chromatography with mass spectrometry

Dongming lignite was sequentially extracted with petroleum ether, carbon disulfide, methanol, acetone, and isometric carbon disulfide/acetone mixed solvent at room temperature to afford extracts 1–5, respectively. High‐performance liquid chromatography coupled with electrospray ionization time‐of‐flight mass spectrometry was used to separate and characterize heteroatomic species in the extracts at molecular level. Molecular mass of compounds in the extracts is mainly distributed from 300 to 800 u, and the relative abundance of compounds with molecular mass over 800 u in the carbon disulfide extract is 135 times of that in the petroleum ether extract. The acetone extract has the highest relative abundance for organonitrogen compounds. Double bond equivalence numbers of detected species indicate that most of the organonitrogen compounds contain N‐heterocyclic aromatic rings, including pyridine, quinoline and pyrrole. Some organonitrogen isomers in Dongming lignite were separated and identified by high‐performance liquid chromatography coupled with electrospray ionization time‐of‐flight mass spectrometry, and the corresponding structural information was proposed.     

Analysis of bioactive components and multi‐component pharmacokinetics of saponins from the leaves of Panax notoginseng in rat plasma after oral administration by LC–MS/MS

In this study, simple ultra‐high performance liquid chromatography coupled with quadrupole time‐of‐flight mass tandem mass spectrometry is used to characterize the absorbed components in rat plasma after the oral administration of saponins from the leaves of Panax notoginseng. Seventeen prototype compounds are structurally characterized. Furthermore, a simple and sensitive liquid chromatography with tandem mass spectrometry method is also used for the simultaneous determination of notoginsenoside Fc, ginsenoside Rb1, ginsenoside Rc, ginsenoside Rb3, ginsenoside Rd, and notoginsenoside Fe in rat plasma within 5 min. After n‐butanol mediated liquid–liquid extraction, all analytes were separated on a C₁₈ column and monitored in negative ion mode. Linearity, sensitivity, intra‐ and inter‐assay precision, accuracy, recovery, matrix effect, and stability were all within acceptable ranges. The validated liquid chromatography with tandem mass spectrometry method is successfully applied to the pharmacokinetic study of saponins from the leaves of Panax notoginseng in rats after oral administration. The results suggest that notoginsenoside Fc and ginsenoside Rb3 showed relatively higher exposure compared with other saponins. All saponins showed a long duration in plasma with a t_1/2 longer than 15 h, except notoginsenoside Fe (t_1/2 = 2.78 h). This study provides important information about the metabolism of saponins from the leaves of Panax notoginseng, which is useful for completely understanding its mechanism of action.     

Rapid identification of erythrocyte phospholipids in Sprague–Dawley rats by ultra high performance liquid chromatography with electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry

A rapid, sensitive, and reliable approach for analyzing five kinds of erythrocyte phospholipids in Sprague–Dawley rats was provided by ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry with MassLynx^TM MassFragment. Improving conventional high performance liquid chromatography techniques, ultra high performance liquid chromatography integrated with quadrupole time‐of‐flight tandem mass spectrometry offers high sensitivity and increased analytical speed by using columns packed with sub‐2 μm particles (1.7 μm), which allows a faster separation to be achieved. Through this method, 83 phospholipids were tentatively characterized based on their mass spectra and tandem mass spectra, as well as by matching the in‐house formula database within a mass error of 5 ppm, including 40 phosphatidylcholines, 24 phosphatidyl ethanolamines, three phosphatidylinositols, six phosphatidylserines, and ten sphingomyelins. Our present results proved that the established method could be used to qualitatively analyze complex erythrocyte phospholipids in Sprague–Dawley rats and provide a useful data base for pharmacology and phospholipidomics to seek potential biomarkers of disease prediction.